PHP Array Operators

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PHP: Array Operators

Description

This is a Comprehensive PHP array operators tutorial from w3resource.com

List of array operators

Name

Example

Result

Union

$x + $y

Union of $x and $y. The + operator appends elements of remaining keys from the right-sided array to the left-handed, but duplicated keys are not overwritten.

Equality

$x == $y

TRUE if $x and $y have the same key/value pairs.

Identity

$x === $y

TRUE if $x and $y have the same key/value pairs in the same order and of the same types.

Inequality

$x != $y

TRUE if $x is not equal to $y.

Inequality

$x <> $y

TRUE if $x is not equal to $y.

Non-identity

$x !== $y

TRUE if $x is not identical to $y.

Example : array union (+) operator

In the following example, the union operator adds the last element from the $b array ($c = $a + $b) with $a array as "c=>" key is not present in $a array. In the second statement ($c = $b + $a) no element is added from $b as all the keys of $a array are present in $b array.

  1. $a = array("a" => "apple", "b" => "banana");  

  2. $b = array("a" => "pear", "b" => "strawberry", "c" => "cherry");  

  3. $c = $a + $b; // Union of $a and $b  

  4. echo "Union of $a and $b : 
    ";  

  5. var_dump($c);  

  6. $c = $b + $a; // Union of $b and $a   

  7. echo "
    Union of $b and $a : 
    ";  

  8. var_dump($c);  

  9. ?>  

Output :

Union of $a and $b :
array(3) { ["a"]=> string(5) "apple" ["b"]=> string(6) "banana" ["c"]=> string(6) "cherry" }
Union of $b and $a :
array(3) { ["a"]=> string(4) "pear" ["b"]=> string(10) "strawberry" ["c"]=> string(6) "cherry" }

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Example : array equality (==) and identity(===) operators

In the following example equality operator returns true as the two arrays have same key/value pairs whereas identity operator returns false as the key/value of the comparing arrays are same but not in same order.

  1. $a = array("1" => "apple", "0" => "banana");  

  2. $b = array( "banana", "apple");  

  3. var_dump($a == $b);  

  4. var_dump($a === $b);  

  5. ?>  

Output :

bool(true) bool(false)